I agree with Roger that you're much better off replacing the SX10 - which is circa 2014 hardware - with a current generation endpoint such as the Room Bar (attendees up to 3 meters away) or Room Bar Pro (attendees up to 6 meters away - but built-in mics limited to 4 meters). Both are Microsoft Teams Rooms (Android) certified and can natively join Webex Meetings when dual registered to Webex Control Hub and Teams Admin Center.
The SX10 is so old that it doesn't even support WebRTC join for Microsoft Teams Meetings. The only way it could join would be through Cisco Video Integration for Microsoft Teams, plus VQ Communications DMA (not an endorsement) if you want One Button to Push since SX series endpoints will no longer be able to utilize the Hybrid Calendar service through Webex Control Hub as of June 2025, or Synergy SKY (also not an endorsement) - none of which are free. Roger's reference to on-premises mode would require the endpoint to either register to an instance of Expressway or CUCM with Expressway; or, perform a direct SIP URI dial without a call control agent. The latter either requires the endpoint to have a public IPv4 address directly (i.e., no NAT) or to only attempt unencrypted SIP over TCP - not TLS - with a firewall/NAT device that supports protocol inspection for SIP and RTP. The latter is notoriously fickle and I'm not sure the two paid interoperability options I listed above even allow non-secure SIP connections at this point.
